Breast cancer, the most commonly diagnosed cancer among women in the United States, is the second leading cause of cancer death (Ries et al., 2010). Current breast cancer incidence rates in the United States are higher among Caucasians than among African Americans. However, breast cancer mortality rates are higher among African Americans than among Caucasians, perhaps due to the tendency of African American women to be diagnosed with more aggressive disease than Caucasian women (Ries et al., 2010). Some ofthe environmental risk factors for breast cancer identified among Caucasian women (e.g., eariy age at menarche, late age at menopause, lack of physical activity) appear to operate differently in African American women (Bernstein et al., 2003). Few genetic studies of breast cancer have included a sufficient number of African American women to determine whether genetic risk factors or the interaction of genetic and environmental risk factors for breast cancer operate similariy in Caucasian and African American women (Jones et al., 2004). Little is understood about the etiology of breast cancer nor do we know what genetic and environmental factors might help explain racial disparities in breast cancer incidence and mortality.